SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '8fcb7bad7e8b4039cb0794966709ec35e733a4d445c6f2ed99d6fbc6d6a77da9' 
  AND token = '6/D/ZDO/yeS1OWKCQt+56bazpKqzSGgHtGBIOjRxc4M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}